Protective Effect of Lemon Peel Polyphenols on Oxidative Stress-Induced Damage to Human Keratinocyte HaCaT Cells Through Activation of the Nrf2/HO-1 Signaling Pathway

Recent Advances in the Inhibition of Membrane Lipid Peroxidation by Food-Borne Plant Polyphenols via the Nrf2/GPx4 Pathway

Lipid peroxidation (LP) leads to changes in the fluidity and permeability of cell membranes, affecting normal cellular function and potentially triggering apoptosis or necrosis. This process is closely correlated with the onset of many diseases. Evidence suggests that the phenolic hydroxyl groups in food-borne plant polyphenols (FPPs) make them effective antioxidants capable of preventing diseases triggered by cell membrane LP. Proper dietary intake of FPPs can attenuate cellular oxidative stress, especially damage to cell membrane phospholipids, by activating the Nrf2/GPx4 pathway. Nuclear factor E2-related factor 2 (Nrf2) is an oxidative stress antagonist. The signaling pathway regulated by Nrf2 is a defense transduction pathway of the organism against external stimuli such as reactive oxygen species and exogenous chemicals. Glutathione peroxidase 4 (GPx4), under the regulation of Nrf2, is the only enzyme that reduces cell membrane lipid peroxides with specificity, thus playing a pivotal role in regulating cellular ferroptosis and counteracting oxidative stress. This study explored the Nrf2/GPx4 pathway mechanism, antioxidant activity of FPPs, and mechanism of LP. It also highlighted the bioprotective properties of FPPs against LP and its associated mechanisms, including (i) activation of the Nrf2/GPx4 pathway, with GPx4 potentially serving as a central target protein, (ii) regulation of antioxidant enzyme activities, leading to a reduction in the production of ROS and other peroxides, and (iii) antioxidant effects on LP and downstream phospholipid structure. In conclusion, FPPs play a crucial role as natural antioxidants in preventing LP. However, further in-depth analysis of FPPs coregulation of multiple signaling pathways is required, and the combined effects of these mechanisms need further evaluation in experimental models. Human trials could provide valuable insights into new directions for research and application.

Exploring Phenolic Compounds in Crop By-Products for Cosmetic Efficacy

Phenolic compounds represent a group of secondary metabolites that serve essential functions in plants. Beyond their positive impact on plants, these phenolic metabolites, often referred to as polyphenols, possess a range of biological properties that can promote skin health. Scientific research indicates that topically using phenolics derived from plants can be advantageous, but their activity and stability highly depend on storage of the source material and the extraction method. These compounds have the ability to relieve symptoms and hinder the progression of different skin diseases. Because they come from natural sources and have minimal toxicity, phenolic compounds show potential in addressing the causes and effects of skin aging, skin diseases, and various types of skin damage, such as wounds and burns. Hence, this review provides extensive information on the particular crops from which by-product phenolic compounds can be sourced, also emphasizing the need to conduct research according to proper plant material storage practices and the choice of the best extracting method, along with an examination of their specific functions and the mechanisms by which they act to protect skin.

Nanofabrication of cobalt-tellurium using Allium sativum extract and its protective efficacy against H2O2-induced oxidative damage in HaCaT cells

Allium sativum (A. sativum)is well known for its therapeutic and culinary uses. Because of their high medicinal properties, the clove extract was selected to synthesize cobalt-tellurium nanoparticles. The aim of the study was to evaluate the protective activity of the nanofabricated cobalt-tellurium using A. sativum (Co-Tel-As-NPs) against H₂O₂-induced oxidative damage in HaCaT cells. Synthesized Co-Tel-As-NPs were analyzed using UV-Visible spectroscopy, FT-IR, EDAX, XRD, DLS, and SEM. Various concentrations of Co-Tel-As-NPs were used as a pretreatment on HaCaT cells before H₂O₂ was added. Then, the cell viability and mitochondrial damage were compared between pretreated and untreated control cells using an array of assays (MTT, LDH, DAPI, MMP, and TEM), and the intracellular ROS, NO, and antioxidant enzyme production were examined. In the present research, Co-Tel-As-NPs at different concentrations (0.5, 1.0, 2.0, and 4.0μg/mL) were tested for toxicity using HaCaT cells. Furthermore, the effect of H₂O₂ on the viability of HaCaT cells was evaluated using the MTT assay for Co-Tel-As-NPs. Among those, Co-Tel-As-NPs at 4.0 μg/mL showed notable protection; with the same treatment, cell viability was discovered to be 91% and LDH leakage was also significantly decreased. Additionally, the measurement of mitochondrial membrane potential was significantly decreased by Co-Tel-As-NPs pretreatment against H₂O₂. The recovery of the condensed and fragmented nuclei brought about by the action of Co-Tel-As-NPs was identified using DAPI staining. TEM examination of the HaCaT cells revealed that the Co-Tel-As-NPs had a therapeutic effect against H₂O₂ keratinocyte damage.

Functional Ingredients and Additives from Lemon by-Products and Their Applications in Food Preservation: A Review

Citrus trees are among the most abundant fruit trees in the world, with an annual production of around 124 million tonnes. Lemons and limes are among the most significant contributors, producing nearly 16 million tonnes per year. The processing and consumption of citrus fruits generates a significant amount of waste, including peels, pulp, seeds, and pomace, which represents about 50% of the fresh fruit. Citrus limon (C. limon) by-products are composed of significant amounts of bioactive compounds, such as phenolic compounds, carotenoids, vitamins, essential oils, and fibres, which give them nutritional value and health benefits such as antimicrobial and antioxidant properties. These by-products, which are typically discarded as waste in the environment, can be explored to produce new functional ingredients, a desirable approach from a circular economy perspective. The present review systematically summarizes the potential high-biological-value components extracted from by-products to achieve a zero-waste goal, focusing on the recovery of three main fractions: essential oils, phenolic compounds, and dietary fibres, present in C. limon by-products, and their applications in food preservation.

Protective effect of human amniotic membrane extract against hydrogen peroxide-induced oxidative damage in human dermal fibroblasts

OBJECTIVE

One of the main approaches to preventing skin ageing is to protect fibroblast cells from oxidative stress. The promoting effect of the human amniotic membrane extract (hAME) on re-epithelization, proliferation and migration of cells in wound healing has been already well studied. This experimental study aimed to investigate the antioxidant activity of hAME against hydrogen peroxide (H₂ O₂ )-induced dermal fibroblast damage.

METHODS

Here, to establish the ageing model, human foreskin fibroblasts (HFFs) were exposed to 200 μM H₂ O₂ for 2 h. HFFs were treated with 0.1 mg/ml AME for 24 or 48 h before or/and after H₂ O₂ exposure. A total of 48 h following the H₂ O₂ treatment, we measured cell proliferation, viability, senescence-associated β-galactosidase (SA-β-Gal), antioxidants and preinflammatory cytokine (IL-6) levels, as well as the expression of senescence-associated genes (P53 and P21).

RESULTS

The obtained results indicated that under oxidative stress, AME significantly increased cellular viability and not only promoted the cell proliferation rate but also attenuated apoptotic induction condition (p < 0.001). AME also significantly reversed the SA-β-Gal levels induced by H₂ O₂ (p < 0.001). Additionally, both pre- and post-treatment regimen by AME down-regulated the expression of senescence marker genes (p < 0.001). Moreover, AME declined different oxidative stress biomarkers such as superoxide dismutase and catalase and increased the glutathione amount.

CONCLUSION

Altogether, our results indicated that AME had a remarkable antioxidant and antiageing activity as pre- and post-treatment regimen, pointing to this compound as a potential natural-based cosmeceutical agent to prevent and treat skin ageing conditions.

Anticancer Effects of Fucoxanthin through Cell Cycle Arrest, Apoptosis Induction, Angiogenesis Inhibition, and Autophagy Modulation

Cancer accounts for one in seven deaths worldwide and is the second leading cause of death in the United States, after heart disease. One of the standard cancer treatments is chemotherapy which sometimes can lead to chemoresistance and treatment failure. Therefore, there is a great need for novel therapeutic approaches to treat these patients. Novel natural products have exhibited anticancer effects that may be beneficial in treating many kinds of cancer, having fewer side effects, low toxicity, and affordability. Numerous marine natural compounds have been found to inhibit molecular events and signaling pathways associated with various stages of cancer development. Fucoxanthin is a well-known marine carotenoid of the xanthophyll family with bioactive compounds. It is profusely found in brown seaweeds, providing more than 10% of the total creation of natural carotenoids. Fucoxanthin is found in edible brown seaweed macroalgae such as Undaria pinnatifida, Laminaria japonica, and Eisenia bicyclis. Many of fucoxanthin's pharmacological properties include antioxidant, anti-tumor, anti-inflammatory, antiobesity, anticancer, and antihypertensive effects. Fucoxanthin inhibits many cancer cell lines' proliferation, angiogenesis, migration, invasion, and metastasis. In addition, it modulates miRNA and induces cell cycle growth arrest, apoptosis, and autophagy. Moreover, the literature shows fucoxanthin's ability to inhibit cytokines and growth factors such as TNF-α and VEGF, which stimulates the activation of downstream signaling pathways such as PI3K/Akt autophagy, and pathways of apoptosis. This review highlights the different critical mechanisms by which fucoxanthin inhibits diverse cancer types, such as breast, prostate, gastric, lung, and bladder development and progression. Moreover, this article reviews the existing literature and provides critical supportive evidence for fucoxanthin's possible therapeutic use in cancer.

Dietary L-theanine supplementation improves lipid metabolism and antioxidant capacity in weaning piglets

The aim of this study was to explore the effects of dietary L-theanine (LT) supplementation on lipid metabolism and antioxidant capacity in weaned piglets. Twenty-one castrated DLY weaning piglets were randomly divided into three groups: a basal diet, a basal diet supplemented with 0.05% and 0.1% LT, respectively. Our data showed that dietary LT supplementation decreased T-CHO, TG, LDL-C and apoB levels and increased apoA and HDL-C levels in serum, but decreased the hepatic TG and T-CHO contents. Dietary LT supplementation increased the antioxidant capacity in serum and liver, and significantly increased the Nrf2 mRNA level and the nucleus Nrf2 protein level, but decreased the mRNA level of keap1 in the liver. In addition, dietary LT supplementation significantly increased HSL enzyme activity and the levels of CPT1 and TBA, while decreasing the enzyme activities of LPL and FAS in the liver. Furthermore, the mRNA levels HMG-CoAR, CPT-1a and PPARα and the protein levels of phosphorylated-AMPK and PGC-1α were increased by LT. Together, our data provide the first evidence that dietary supplementation of LT could improve lipid metabolism and antioxidant capacity in the liver of weaned piglets, and the effect might be mediated by activation of AMPK and Nrf2 signaling, respectively.

Polyphenols in Ilex latifolia Thunb. inhibit human lung cancer cell line A549 by regulation of the PI3K-Akt signaling pathway

Background

The leaves of the plant Ilex latifolia Thunb. can be made into Kuding tea, which is a drink rich in polyphenols. This study aimed to observe the effect of Ilex latifolia Thunb. polyphenols (ILTPs) on human lung cancer cell line A549 (A549 cells) by regulating the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway.

Methods

In vitro cultured cells were treated with ILTPs; the proliferation of A549 cells and BEAS-2B human normal lung epithelial cells (Beas-2B cells) was observed using the 3-(4,5-dimethylazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the survival status of A549 cells was observed by fluorescence staining. The expression of A549 cells was observed by quantitative polymerase chain reaction (qPCR) assay and Western blot analysis, while the compound composition of ILTPs was detected using high-performance liquid chromatography (HPLC).

Results

The experimental results showed that the proliferation of Beas-2B cells was unaffected by treatment with 0–500 μg/mL of ILTPs, whereas the decreased proliferation of A549 cells was observed with the increasing concentrations of ILTPs. Additionally, ILTPs elevated the levels of lactate dehydrogenase (LDH) and reactive oxygen species (ROS) and promoted apoptosis in A549 cells. The results of qPCR experiments showed that ILTPs upregulated caspase-9 mRNA expression and downregulated phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), mammalian target of rapamycin (mTOR), B-cell lymphoma-2 (Bcl-2), nuclear factor-κB (NF-κB), vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1 alpha (HIF-1α), and cyclooxygenase-2 (COX-2) expression in A549 cells. The Western blot analysis results also showed that ILTPs could reduce the protein expression of PI3K and Akt. The HPLC results showed that the main compounds present in the ILTPs were rutin, kaempferol, isochlorogenic acid A, isochlorogenic acid B, and isochlorogenic acid C.

Conclusions

Thus, this study indicated that the polyphenols of I. latifolia act as a class of natural functional food materials that potently suppress cancer by exerting their inhibitory effects on A549 cell proliferation through five key polyphenolic compounds.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03568-3.

Anti-Inflammatory Effects of Metabolites from Antarctic Fungal Strain Pleosporales sp. SF-7343 in HaCaT Human Keratinocytes

Chemical investigation of the Antarctic fungi Pleosporales sp. SF-7343 revealed four known secondary fungal metabolites: alternate C (1), altenusin (2), alternariol (3), and altenuene (4). The compound structures were identified primarily by NMR and MS analyses. Atopic dermatitis, an inflammatory disease, is driven by the abnormal activation of T helper (Th) 2 cells and barrier dysfunction. We attempted to identify the anti-inflammatory components of SF-7343. Initial screening showed that compounds 1 and 3 inhibited the secretion of interleukin-8 and -6 in tumor necrosis factor-α/interferon-γ-treated HaCaT cells, and these compounds also showed inhibitory effects on CCL5 and CCL22. Compounds 1 and 3 also downregulated the protein expression levels of intercellular adhesion molecule-1 and upregulated the expression of filaggrin and involcurin. The mechanism study results showed that compounds 1 and 3 inhibited nuclear translocation of nuclear factor-kappa B p65 and the phosphorylation of STAT1 and STAT3. Compound 1, but not compound 3, significantly promoted the expression of heme oxygenase (HO)-1. The effects of compound 1 were partly reversed by co-treatment with a HO-1 inhibitor, tin protoporphyrin IX. Taken together, this study demonstrates the potential value of Antarctic fungal strain SF-7343 isolates as a bioresource for bioactive compounds to prevent skin inflammation.

Ultrasound-Assisted Extraction Optimization of Proanthocyanidins from Kiwi (Actinidia chinensis) Leaves and Evaluation of Its Antioxidant Activity

Using ultrasound (US) in proanthocyanidin (PA) extraction has become one of the important emerging technologies. It could be the next generation for studying the US mechnophore impact on the bioactive compound’s functionality. The objective of this study was to demonstrate the potential of US treatment on PAs extracted from kiwifruit (Actinidia chinensis) leaves, and to provide a comprehensive chemical composition and bioactivity relationship of the purified kiwifruit leaves PAs (PKLPs). Several methods like single-factor experiments and response surface methodology (RSM) for the four affected factors on US extraction efficiency were constructed. HPLC-QTOF-MS/MS, cytotoxicity analysis, and antioxidant activity were also demonstrated. In the results, the modeling of PA affected factors showed that 40% US-amplitude, 30 mL/g dry weight (DW) solvent to solid ration (S/S), and 70 °C for 15 min were the optimum conditions for the extraction of PAs. Furthermore, PKLPs exhibited significant radical scavenging and cellular antioxidant activity (p < 0.05). In conclusion, this study’s novelty comes from the broad prospects of using US in PKLP green extraction that could play an important role in maximizing this phytochemical functionality in drug discovery and food science fields.